Look for most public safety ops to be on the MPSCS TRS, and a few of the interoperability channels listed at this location. Out of all of those listed, 155.865 MHz should be the most active. Likewise, EMS Ops maybe on 155.235 MHz.
I just overheard some traffic that fire crews at MIS are on 452.3000 MHz. Might be a good idea to monitor this frequency in case anything goes wrong, or there is a large accident.